svn commit: r363495 - in head/sys/x86: include x86

[Alexander Motin]

Author: mav
Date: Fri Jul 24 20:52:09 2020
New Revision: 363495
URL: https://svnweb.freebsd.org/changeset/base/363495

Log:
  Introduce ipi_self_from_nmi().
  
  It allows safe IPI sending to current CPU from NMI context.
  
  Unlike other ipi_*() functions this waits for delivery to leave LAPIC in
  a state safe for interrupted code.
  
  MFC after:	2 weeks
  Sponsored by:	iXsystems, Inc.

Modified:
  head/sys/x86/include/x86_smp.h
  head/sys/x86/x86/mp_x86.c

Modified: head/sys/x86/include/x86_smp.h
==============================================================================
--- head/sys/x86/include/x86_smp.h	Fri Jul 24 20:48:06 2020	(r363494)
+++ head/sys/x86/include/x86_smp.h	Fri Jul 24 20:52:09 2020	(r363495)
@@ -97,6 +97,7 @@ void 	ipi_bitmap_handler(struct trapframe frame);
 void	ipi_cpu(int cpu, u_int ipi);
 int	ipi_nmi_handler(void);
 void	ipi_selected(cpuset_t cpus, u_int ipi);
+void	ipi_self_from_nmi(u_int vector);
 void	set_interrupt_apic_ids(void);
 void	smp_cache_flush(smp_invl_cb_t curcpu_cb);
 void	smp_masked_invlpg(cpuset_t mask, vm_offset_t addr, struct pmap *pmap,

Modified: head/sys/x86/x86/mp_x86.c
==============================================================================
--- head/sys/x86/x86/mp_x86.c	Fri Jul 24 20:48:06 2020	(r363494)
+++ head/sys/x86/x86/mp_x86.c	Fri Jul 24 20:52:09 2020	(r363495)
@@ -1398,6 +1398,21 @@ ipi_all_but_self(u_int ipi)
 	lapic_ipi_vectored(ipi, APIC_IPI_DEST_OTHERS);
 }
 
+void
+ipi_self_from_nmi(u_int vector)
+{
+
+	lapic_ipi_vectored(vector, APIC_IPI_DEST_SELF);
+
+	/* Wait for IPI to finish. */
+	if (!lapic_ipi_wait(50000)) {
+		if (KERNEL_PANICKED())
+			return;
+		else
+			panic("APIC: IPI is stuck");
+	}
+}
+
 int
 ipi_nmi_handler(void)
 {